


False Positive

by BuruRaven



Category: Ao no Exorcist | Blue Exorcist
Genre: Based On A Dead Theory, Canon Compliant Up To Chapter 71, Gen, No Slash
Language: English
Status: Completed
Published: 2015-09-20
Updated: 2015-09-20
Packaged: 2018-04-22 13:01:36
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,313
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/4836350
Author URL: https://archiveofourown.org/users/BuruRaven/pseuds/BuruRaven
Summary: <blockquote class="userstuff">
              <p>
  <i>“Yukio-kun?” Came the worried female voice from the other side of the line.</i>
  <br/>
  <i>“Sensei?”</i>
  <br/>
  <i>“I am afraid you’ll have to come down by the medical centre again later today…”</i>
  <br/>
  <i>Yukio tried to hide his panic.</i>
  <br/>
  <i>“That should be no problem. But… is there something wrong?”</i>
  <br/>
  <i>“Haha… this happens sometimes, so it’s nothing to be worried about, Yukio-kun… really… But er… you see… your laboratory test results came out quite different from what they usually look like…”</i>
</p><p>This little thing is based on <a href="http://bururaven.tumblr.com/post/127861878349/oh-i-hadnt-noticed-thats-a-conjuration">this post</a>, which takes a far-fetched conclusion out of one incorrect premise. Because now I know this will never be canon, but I do like that wrong theory so much, I decided to engrave it for posterity! Horrible, I know. This is the result.<br/>This fic was originally posted on my tumblr on September 13th, 2015, <a href="http://bururaven.tumblr.com/post/128981262559/false-positive">here</a>.</p>
            </blockquote>





	False Positive

**Author's Note:**

> Disclaimer: I don’t own Ao no Exorcist/Blue Exorcist. Ao no Exorcist/Blue Exorcist is the property of Kazue Katō, and is not my intellectual property. There is no financial gain made from this, nor will any be sought. This is for entertainment purposes only.

In a quick, effective movement, Yukio adjusted the glasses atop of his nose with one finger. It had been almost two weeks since the beginning of his late-night experiments and they had all been resounding failures so far. Just how far could he go without actually dying?

He straightened up minutely and knocked on the door in front of him.

“Yes?” Came the muffled female reply. Yukio opened the door and peeked inside politely.

“Middle First Class Exorcist, Okumura Yukio. I came for my usual check-up.”

“Oh, Yukio-kun! Come in, come in! Can you sit on that stretcher over there by the window, please? The nurse will take your blood for analysis and I’ll meet you in a minute.” The doctor told him from behind one of the folding screens on the other side of the room.

Yukio did as he was told. He stripped of his overcoat, sat on the stretcher and waited. He had uncharacteristically come to do his usual medical check-up during the lunch break so he could use more time at the end of the day to continue conducting his experiments.

What else did he have to do to squeeze the power out of him? He almost died for good the previous night. And he was terrified back then, he really did believe that he was not going to make it out of it alive…! He must be doing something wrong. But what?

While pondering over this issue, Yukio’s eyes wandered out of the window. Outside, three stories down, on the ground level, he could see some kids sitting on the edge of the fountain in the middle of the square. He recognized Rin’s messy black hair. The blonde girl by his side must’ve been Shiemi-san and the little guy standing in front of them looked like Miwa-san. The forth individual, sitting a little distant from the other three looked like Takara-san.

“…Okumura-san?” Yukio flinched at being called from such a close distance. He hadn’t even noticed the nurse approaching. He was holding the needle ready and staring at Yukio with an odd expression. It looked like he had called Yukio’s name several times already.

“Oh yes, sure. Sorry.” The young exorcist replied awkwardly, lifting up his left sleeve to give access to his arm veins.

Yukio looked back out of the window the moment the needle pierced his skin only to be greeted with a blue human-shaped torch jumping on Takara with apparent murderous intent and a clearly unsheathed Kurikara.

“Nii-san!!” Yukio reprimanded, even though Rin couldn’t hear him form that distance.

He could hear Shiemi’s and Konekomaru’s unison reprimand, though. Rin stopped his attack and extinguished the flames just as fast as they had appeared. Yukio shook his head.

The nurse chuckled softly by his side.

“He’s a handful, that brother of yours.” He commented, while diligently labelling the vial with the blood he had just collected.

“You have no idea.”

* * *

 

“Yukio-kun?” Came the worried female voice from the other side of the line.

“Sensei?”

“I am afraid you’ll have to come down by the medical centre again later today…”

Yukio tried to hide his panic.

“That should be no problem. But… is there something wrong?”

“Haha… this happens sometimes, so it’s nothing to be worried about, Yukio-kun… really… But er… you see… your laboratory test results came out quite different from what they usually look like…”

Yukio felt faint. He stopped his progress up the stairs to his and Rin’s room.

“…it was probably a contaminated vial. Damn Coal Tar always getting themselves into weird places…! Hehe.” A pause. Then a small sigh. “If it were anyone else, I wouldn’t even call them before tomorrow. But, as it is you, Yukio-kun, we need to make sure. I’m sure you understand. So, will you come by as soon as you can?”

Yukio sat down on the cold stairs. He dry-gulped. This was it. They’d found out. He was going to be locked away somewhere and used as a lab rat.

“…Yukio-kun?”

“Yes. Sure. I understand. I’m at the dormitory right now, but I’ll go straight back. I’ll be there in 20 minutes.”

“That’s wonderful! I’ll do the blood collecting myself and I’ll make sure nothing gets contaminated this time. I’m sure this was just a false positive. Those happen. Nothing is ever completely error-free.” Another pause, longer this time. “Don’t worry, Yukio-kun, I’m sure it’s nothing.”

“Yes.” Yukio agreed in a tone that tried to mimic the doctor’s own reassuring one.

“Alright, then. We’ll be waiting here. See you in 20 minutes.”

The call was terminated.

For a few seconds, Yukio just sat there. Then, he took a deep breath and walked up the rest of the stairs. He knew this day would come sooner or later. There was no running from this. No. He could literally not run away from this. They would hunt him down and, if they couldn’t catch him, [Morinas](http://www.mangapanda.com/ao-no-exorcist/44/11) certainly would. This was it.

Rin was unexpectedly sitting on his desk, studying. If it were any other day, Yukio would’ve been shocked. Right now he simply noted that fact in an absent-minded way.

“I’m back.”

“Welcome back.” Rin turned on his chair to look at him, Bon’s hairpin keeping his fringe in check and a hopeful expression on his face. “Are you coming for dinner today? I got some delicious, fresh shiitake-”

“No.” Yukio interrupted. He put his bag on the chair by his desk. “I’m going back to the academy. I need to stop by the medical centre again.”

“Geez… they’ll dry your veins out that way!” Rin commented with a mildly worried expression. “Are you okay? You look pale. Is there something wrong?”

“No. It’s probably just a lab mistake.” Maybe if he repeated it enough times he would believe it himself.

“Ah, that sucks…”

“Yeah. I’m leaving.” Yukio replied over his shoulder, already halfway to the door.

“Hey, if they let you out soon, please come to dinner…!”

“Yeah-yeah… You study, Nii-san. Meister’s exam is next month.” He said right before shutting the door behind him.

He could hear Rin’s muffled “I know that!!” from inside.

If they let him out soon, Rin said… There’s a chance that Yukio won’t be coming back to this dormitory today, he thought gloomily. No… there’s a chance that he’ll  _never_  come back.

* * *

 

In the end, the results came back negative, meaning, completely human and normal.

“Hehe, see, Yukio-kun? I told you there was nothing to worry about.” Said the doctor with a relieved expression, as the two other exorcists in the room left. Yukio had never seen their faces before. They had just stayed there, on the other side of the room, talking to each other in quiet tones while the doctor collected and analysed Yukio’s blood. Now that they were gone, the doctor was openly smiling at Yukio, sincere happiness stretching on her kind features.

“You can go home now, Yukio-kun. I’m sorry you had to come back here on purpose just so we could get the result we already knew we would get. Damn Coal Tar keep causing this kind of trouble every once in a while. Silly little things. Hehe.”

* * *

 

In the end, Yukio did make it in time for dinner.

He didn’t think he would be able to effectively proceed with his experiments after the day’s events, so he decided on a break for the day.

Rin was ecstatic and Kuro seemed infected by his good spirits. Even Yukio felt a little less gloomy himself. Or maybe he was just relieved.

As always, his brother’s cooking was spot on.

It was nice.

* * *

 

In the end, Yukio couldn’t sleep.

There had been no contamination. Yukio knew this. He had watched as the nurse carefully prepared, labelled and stowed the vial with his blood. There were no Coal Tars in sight and the process had been flawless. He had closely watched the nurses do it countless times, he  _knew_. There had been no  _false_  positive, there had only been a positive. His blood had accused  _demon_. And now it had accused human. How was this possible? Had the first result been in some way caused by the experiments he had been conducting? But, if yes, how could that be if they had been all failures and Yukio hadn’t been able to awaken his powers ever since he met Lucifer weeks ago? Also, if it had been caused by them, then how come he was back to a normal test result again?

He turned on his side, restless. Rin was peacefully asleep on the other side of the room. Sprawled on his back, comforter wacky and a sleeping Kuro atop of his belly, always the perfect image of imperfection. And ignorant peace. Yukio envied him so much.

There must have been something different today. Something about Yukio that had momentarily changed at the time the blood was collected. Something that had never happened before. Something…

Yukio’s eyes slid towards Rin’s desk. Leaning against it, unprotected and unwatched, was Kurikara, like it very often was whenever Rin forgot to lock it in one of the drawers by his bed with the [Key of Vanishment](http://www.mangapanda.com/ao-no-exorcist/1/34). One day, someone or something would come in through the open window, grab the sword and run for it.

Suddenly, Yukio remembered what had been different. Rin had unsheathed the sword during Yukio’s venipuncture. But that was silly. How could that have anything to do with it? Yukio was just tired. It had certainly been some kind of laboratory mistake, he should just forget about it…

Yukio was about to discard his whole train of thought, finally lulled into unconsciousness by Rin’s rhythmic soft snores, when something stirred him into full wakefulness again. Back at Inari, when Yukio met Lucifer, Rin had unsheathed the sword. Back in Tokyo, while he was fighting Tōdō, even though he didn’t know it at the time, Rin was fighting the Impure King, sword unsheathed as well. Were these merely coincidences?

Yukio focused on the sword for a few seconds, then made a decision. If he was right, he didn’t even need to put himself in danger this time.

Silently, he got up and walked to the other side of the room. He grabbed the sword smoothly but, on turning back, he hit his shin on the [Kotatsu](http://www.mangapanda.com/ao-no-exorcist/69) Rin had brought home a few weeks ago. Rin didn’t even stir. Kuro’s tails shook a bit, but he didn’t wake up. Catastrophe averted, Yukio walked back to his side of the room to grab the mirror he used for shaving. Then, went silently just outside of their room, keeping the door just slightly ajar behind him. The corridor right outside their room was empty, dark and cold, only illuminated by the moonshine.

Yukio took the sword out of its protective cloth bag and then held the mirror to his own face. Slowly he unsheathed the sword just a little. Blue shone softly against the side of Yukio’s face but not in his eyes. The teen took a deep breath and focused on remembering the fear he had felt during his encounter with Lucifer.

_[“I want you.”](http://www.mangapanda.com/ao-no-exorcist/67/15) _

As panic started rising in his chest, so did everything assume a more blueish shade. Suddenly, fiery-blue demonic eyes were staring back at him in the mirror. Yukio gasped in shock, back hitting the wall behind him, the hand holding the mirror shacking violently. He rushed to sheath Kurikara and the blue vanished without a trace. His hand threatened to drop the mirror it was holding, but he was able to reign on it and slowly, steadily lower both his hands to his sides. The door to their room whispered on its hinges.

“Wha’ ‘re you doin’?” Rin groggily asked beside him, peeking from inside the room. “Kuro said you took Kurikara and… did you unsheathe it? Why did you do that?” A sleepy Kuro snitch peeked from the doorway too.

So he  _was_  awake. Damn familiar. Yukio had to think of something fast.

“You forgot to hide it again, Nii-san. It was just there, with the window wide open, it’s like you’re purposefully exposing your weakness to the world.”

Rin just stared at him bleary-eyed.

“I easily took it and you didn’t even notice. I unsheathed it to see just how far I had to go until you realized it had been taken.”

“Oh!” Rin exclaimed, realization finally dawning on his sleepy brain. “Kuro saw you taking it but it was you, so it should be okay.”

“Yes, but  _you_  didn’t. I had to unsheathe it, otherwise you would’ve never noticed. I am disappointed, Nii-san.”

“Oh. I… er… Yeah. Understood. I’ll be more careful. I promise.” Rin stated solemnly. “But… I didn’t wake up because you unsheathed it, you know. It was weird… it felt like you were calling me or something. I must’ve dreamt it. Hehe.”

Rin scratched his head embarrassed.

“Well…” He said, stretching his right hand towards the sword to retrieve it from Yukio’s grasp.

Yukio instinctively flinched away. He was shocked by his own reaction. For some reason, he didn’t want to give Rin his sword.

Rin was suddenly very awake, a crease starting to show on his now serious face. He dropped his hand and stared Yukio in the eye.

“Yukio, give it back.” He said slowly.

Yukio willed the arm holding the sword to lift in Rin’s general direction, achieving an oddly mechanical forced-looking movement. Slowly, Rin retrieved the sword from Yukio’s hold. They stared silently at each other for a few seconds. Then, Rin shook his head and sighed.

“Go back to sleep, okay? You look pale.” He said in a tired, but kind tone and turned on himself to walk back inside the room.

Yukio just stood there, put his back to the wall and let himself slowly slide towards the floor, staring into nothingness.

What did this mean?

**Author's Note:**

> It meant nothing, Yukio. Because, as I’ve said above, this whole thing is based on a wrong premise. Though it was fun to write.  
> I hope that, if you read it so far, you enjoyed it at least a bit. Kudos and comments are always appreciated. (^_^) And my [tumblr](http://bururaven.tumblr.com/) askbox is open to everyone.


End file.
